so, what am I missing here? the `Combustivel` **MUST** be embedded, I can't change that

The stacktrace

[EL Warning]: 2013-03-21 10:59:34.659--UnitOfWork(12940738)--Thread(Thread[main,6,main])--Local Exception Stack:
Exception [EclipseLink-6002] (Eclipse Persistence Services - 2.4.1.v20121003-ad44345): org.eclipse.persistence.exceptions.QueryException
Exception Description: Aggregated objects cannot be written/deleted/queried independently from their owners.
Descriptor: [RelationalDescriptor(br.com.germantech.ecf.dominio.modelo.produto.Combustivel --> [])]
Query: DeleteObjectQuery(br.com.germantech.ecf.dominio.modelo.produto.Combustivel@d4ca28)
at org.eclipse.persistence.exceptions.QueryException.aggregateObjectCannotBeDeletedOrWritten(QueryException.java:240)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.prepare(ObjectLevelModifyQuery.java:205)
at org.eclipse.persistence.queries.DeleteObjectQuery.prepare(DeleteObjectQuery.java:327)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:614)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:575)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:820)
at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:751)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
at org.eclipse.persistence.queries.DeleteObjectQuery.executeInUnitOfWorkObjectLevelModifyQuery(DeleteObjectQuery.java:119)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2875)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1602)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1584)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1535)
at org.eclipse.persistence.queries.DeleteObjectQuery.executeDatabaseQuery(DeleteObjectQuery.java:194)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:852)
at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:751)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
at org.eclipse.persistence.queries.DeleteObjectQuery.executeInUnitOfWorkObjectLevelModifyQuery(DeleteObjectQuery.java:119)
at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2875)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1602)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1584)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1535)
at org.eclipse.persistence.internal.sessions.CommitManager.deleteAllObjects(CommitManager.java:334)
at org.eclipse.persistence.internal.sessions.CommitManager.deleteAllObjects(CommitManager.java:283)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1422)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitToDatabase(RepeatableWriteUnitOfWork.java:634)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1509)
at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:266)
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1147)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:84)
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:63)
at br.com.germantech.ecf.aplicacao.interceptors.TransactionInterceptor.invoke(TransactionInterceptor.java:61)
at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:72)
at com.google.inject.internal.InterceptorStackCallback.intercept(InterceptorStackCallback.java:52)
at br.com.germantech.ecf.infraestrutura.persistencia.repositorios.ProdutoRepositoryImpl$$EnhancerByGuice$$d68cdfa4.delete(<generated>)
at br.com.germantech.ecf.infraestrutura.persistencia.repositorios.ProdutoRepositoryImpl.delete(ProdutoRepositoryImpl.java:1)
at br.com.germantech.ecf.aplicacao.services.ProdutoService.delete(ProdutoService.java:66)
at br.com.germantech.ecf.telas.editors.ProdutoEditor.excluirRegistro(ProdutoEditor.java:231)
at br.com.germantech.ecf.telas.editors.GermantechEditor$2.widgetSelected(GermantechEditor.java:108)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:248)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4169)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3758)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at br.com.germantech.ecf.aplicacao.internal.Application.start(Application.java:39)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
at org.eclipse.equinox.launcher.Main.main(Main.java:1414)